Lamp base



FIG. 1 shows a perspective view of my claimed design.

FIG. 2 shows a side view of my claimed design, the other side being identical.

FIG. 3 shows a front view of my claimed design, the rear view being identical.

FIG. 4 shows a top view of my claimed design; and,

FIG. 5 shows a bottom view of my claimed design.

The broken line showing of a lamp shade is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a lamp base, as shown and described. 